1. Field of the Invention
The present invention relates to a camera control system suitable for use in a video conference system, monitor camera, or similar imaging systems.
2. Description of the Related Art
It is known in the art to take an image via a camera and display the image on a screen of a display device such as a CRT wherein the camera is panned or tilted by means of remote control while watching the image on the screen. FIG. 7 illustrates an example of a display screen of such a camera control system. In FIG. 7, an image 602 of an object is taken via a camera and displayed in a view window 601. The direction of the camera can be changed (tilted) in vertical directions in response to the designation given via buttons 603 and 604. Similarly, the direction of the camera can be changed (panned) in horizontal directions in response to the designation given via buttons 605 and 606. In FIG. 7, there is also shown a cursor 607 on the screen. If the cursor 607 is put on any button 603-606 with a mouse or similar device and clicked, the pick-up direction of the camera can be changed in a desired direction.
However, in the conventional technique described above, no information is displayed on the screen about the range within which the direction of the camera can be changed, and a user cannot know the range within which he/she can change the pick-up direction of the camera. Furthermore, when it is desired to rotate the camera by a large amount so as to make a great change in the pick-up direction of the camera, it is required to click a button (603-606) a great number of times, which is a tedious operation for a user.
Furthermore, in the above technique, the pick-up direction of the camera is controlled in an incremental or decremental fashion relative to a previous direction, and it is impossible to control the viewing direction by designating the absolute camera position or absolute camera angle. For example, when the camera is remote-controlled, there is a time lag between the time of transmitting an operation command and the time of receiving an image from the camera, and thus the pick-up direction of the camera is often changed excessively beyond a desired direction. This makes it difficult to properly control the viewing direction of the camera.